| 摘要 |
<p>A self sustaining autoclaved article of apparent density of 15-40 lbs/cu. ft. and a transverse strength in excess of 100 lbs/sq. inch comprises a dense matrix of calcium silicate hydrate with 16-70% by volume of macroscopic spherical voids, and fibres at a density of 0,25-5,0 lbs/cu. ft., and at least 90% having a length between 0,3 to 2,5 centimetres. Fibres specified are asbestos and cellulosic e.g. bagasse plant stems and aspen wood, and the cellulosic fibres are pre-soaked in water, caustic soda or sodium silicate before incorporating in the slurry from which the article is moulded. For the higher density product fillers, e.g. sand or gravel, are added. The products are obtained by forming a stable foamed aqueous slurry of the components and autoclaving under steam pressure to react the calcareous and siliceous materials. Specified are calcareous-burnt and hydrated lime, portland cement, lime containing hydraulic and natural cements, and their mixtures; siliceousdiatomaceous earth, artificial or natural pezzolanas, sand, fly ash, ground silica and their mixtures. The foam is pre-formed by gassifying a dilute solution of a foaming agent in water, e.g. saponin, peptones, albumin, soap bark, water soluble cellulose ethers, hydrated cellulose dispersions, alkyl-naphthalene sulphonates, stabilized soaps and hydrolized proteins. Foam stabilizers e.g. burtenite may be added.</p> |
